Six degrees of pharmacology

"What's your Abel number?" was the big question being asked by pharmacologists this week at the Experimental Biology meeting
in Washington, DC.

Members of the American Society of Pharmacology and Experimental Therapeutics (ASPET) were swept up in a game, akin to playing
six degrees of separation, in which researchers compete to be the most closely related to the man regarded as the field's
founder: John J. Abel.

Thanks to a project initiated by David Bylund of the University of Nebraska in Omaha, attendees were wearing large pins proclaiming
their pedigree. "How did you get to be a 3?" and "I got myself down to a 5," became the hot conversation starters at society
mixers.

Abel pioneered the discipline of pharmacology in the late nineteenth century, forming departments at the University of Michigan
and Johns Hopkins University, and founding ASPET. Most famous for his work isolating adrenaline, an important stress hormone,
Abel published almost 100 papers during his career. These papers are shared with a total of 27 co-authors, who, in the new
game, are assigned an 'Abel number' of 1. Those 27 scientists co-published with at least 278 individuals (who get an Abel
number of 2), who in turn published with at least 3,000 more (Abel number 3s).

Bylund borrowed the idea from mathematicians, who define themselves with an Erdos number to see how close they are to the
late and extremely prolific Hungarian mathematician Paul Erdos. A slew of such linking games have been invented across a range
of topics, including 'six degrees of Kevin Bacon', which attempts to link movie actors through co-appearance in films, and
'six degrees of wikipedia', which links encyclopaedia articles.

Happy anniversary

Bylund pitched the Abel-number idea to ASPET, which will celebrate its centennial next year. "This was one activity we wanted
to roll out early," says planning-committee member Stephanie Watts.

At this year's meeting, scientists who visited the ASPET booth submitted pertinent references to get their Abel-number pins.
But Bylund is also working on a massive database to work out the entire community's numbers; researchers can contribute their
references by e-mail as outlined on the ASPET website.

Combing through citations to generate the Abel numbers is laborious, says Bylund, even with many journal archives online.
"Sixty-five per cent of the 2s are done," said Bylund. "We'll never get all the 3s."

Abel numbers express connections rather than prominence, acting more like a family tree than a citation index. But lower numbers
are still perceived as conveying some stature. Alice Young of Texas Tech University in Lubbock says she was proud to be one
of very few women wearing a 3. Watts, from Michigan State University, upgraded her 6 to a 5 after seeing someone she'd published
with who was wearing a 4. "We all want to move up," she says. Some with higher numbers rationalized that this simply indicated
their youth.

The competitive underbelly of the game has spawned some good-natured disgruntlement. When ASPET past-president James Barrett
learned he was only a 6, he played a practical joke on Bylund, sending an e-mail apparently lodging a formal protest about
the rules; he contested in detail the notion that co-authorship of books rather than papers doesn't count towards an Abel
number. Byland didn't realize the message was in jest until the two men met later in the week.

Mischief aside, Barrett says the project has created camaraderie across disciplines and a heritage within the society. "It
links us to a lineage that goes back 100 years," he says.